1. Field of the Invention
The present invention relates to a process for the production of a semiconductor device, which comprises forming a film of a radiation-sensitive polymer and patterning the formed film.
2. Description of the Related Art
In the production of integrated circuits, an increase of the density and integration degree of elements is urgently required, and the development and establishment of ultrafine processing techniques of circuit patterns are progressing rapidly. In lithographic processes, methods of forming patterns by using high-energy radiation having a short wavelength, such as far ultraviolet rays, X-rays, and electron beams, instead of the ultraviolet rays heretofore used, have been developed, and with this development, the establishment of a technique of providing a high-performance resist material sensitive to these radiations is indispensable. In the production of integrated circuits, a method is adopted in which a resist material is coated on a substrate, exposed and developed to form a fine pattern, and using the obtained pattern as a mask, the substrate is etched. In this production method, the resist must have a high sensitivity and a high resolution such that a fine pattern on the submicron order can be obtained. Further, for the etching method, the wet etching method giving a large side etching has been replaced by the dry etching method. Accordingly, the resist must have a dry etching resistance. Very few resists, however, satisfy all of these requirements.
As the means for solving the problem of the dry etching resistance and the problem of the deviation of the resolution owing to the dispersion of the resist thickness caused by the uneven surface of the substrate, a two-layer resist method is adopted which comprises forming a thick planarizing layer of an organic material on the substrate and coating a resist material thinly on the planarizing layer to obtain a high sensitivity and a high resolution.
In the two-layer resist method, a polymer containing Si is used for the top layer, patterning is performed by light exposure and development of the top layer, and the bottom layer is etched by using the top layer as the mask by an oxygen reactive ion etching (O.sub.2 RIE) to form a pattern. In this method, however, the steps are more complicated than in the single-layer resist method, and a reduction of the yield and throughput occurs. Accordingly, a simplification of the steps is desired.
The catalytic decomposition of trimethylsilyl poly(vinylphenol) in the presence of photo acid generator is disclosed in Microelectronic Engineering, 6 (1987), pages 393-398 (North-Holland), but the dry-etching process for this resist composition is not disclosed.
A process using a polymer containing organosilicon monomers as the X-ray resist and dry-developing this resist with O.sub.2 plasma is disclosed in J. Vac. Sci. Technol., 19, No. 4, pages 872-880 (1981). In this process, the organosilicon monomers are fixed to the light-exposed area to act as the mask for oxygen reactive ion etching, and a negative resist pattern is formed.